<template>
<div class="goods-sku">
    <dl v-for="item in goods.specs" :key="item.id">
        <dt>{{ item.name }}</dt>
        <dd>
            <template v-for="val in item.values" :key="val.name">
                <img
                        :class="{ selected: val.selected }"
                        @click="clickSpecs(item,val)"
                        v-if="val.picture"
                        :title="val.name"
                        :src="val.picture">
                <span :class="{ selected: val.selected }" @click="clickSpecs(item, val)" v-else>{{ val.name }}</span>
            </template>
        </dd>
    </dl>
</div>
</template>

<script setup>
import getPowerSet from '@/vender/power-set'
// 根据skus数据得到路径字典对象
const spliter = '★'

// 得到当前选中规格集合
const getSelectedArr = (specs) => {
    const selectedArr = []
    specs.forEach(spec => {
        const selectedVal = spec.values.find(val => val.selected)
        selectedArr.push(selectedVal ? selectedVal.name : undefined)
    })
    return selectedArr
}
const getPathMap = (skus) => {
    const pathMap = {}
    skus.forEach(sku => {
        // 1. 过滤出有库存有效的sku
        if (sku.inventory) {
            // 2. 得到sku属性值数组
            const specs = sku.specs.map(spec => spec.valueName)
            // 3. 得到sku属性值数组的子集
            const powerSet = getPowerSet(specs)
            // 4. 设置给路径字典对象
            powerSet.forEach(set => {
                const key = set.join(spliter)
                if (pathMap[key]) {
                    // 已经有key往数组追加
                    pathMap[key].push(sku.id)
                } else {
                    // 没有key设置一个数组
                    pathMap[key] = [sku.id]
                }
            })
        }
    })
    return pathMap
}

// 更新按钮的禁用状态
const updateDisabledStatus = (specs, pathMap) => {
    specs.forEach((spec, i) => {
        const selectedArr = getSelectedArr(specs)
        spec.values.forEach(val => {
            // 已经选中的按钮不用判断
            if (val.name === selectedArr[i]) return false
            // 未选中的替换对应的值
            selectedArr[i] = val.name
            // 过滤无效值得到key
            const key = selectedArr.filter(v => v).join(spliter)
            // 设置禁用状态
            val.disabled = !pathMap[key]
        })
    })
}

// 初始化选中状态
const initSelectedStatus = (goods, skuId) => {
    const sku = goods.skus.find(sku => sku.id === skuId)
    if (sku) {
        goods.specs.forEach((spec, i) => {
            const value = sku.specs[i].valueName
            spec.values.forEach(val => {
                val.selected = val.name === value
            })
        })
    }
}

const props = defineProps({
    goods: {
        type: Object,
        default: () => ({specs: [], skus: [] })
    },
    skuId: {
        type: String,
        default: ''
    }
})

const emit = defineEmits(['change'])

// 根据传入的skuId默认选中的规格按钮
initSelectedStatus(props.goods, props.skuId)

// 组件初始化的时候更新禁用状态
updateDisabledStatus(props.goods.specs, getPathMap(props.goods.skus))


const clickSpecs = (item, val) => {
    // 如果是禁用状态不作为
    if (val.disabled) return false
    // 1. 选中与取消逻辑
    if (val.selected) {
        val.selected = false
    } else {
        item.values.forEach(item => {
            item.selected = false
        })
        val.selected = true
    }
    // 点击的时候更新禁用状态
    updateDisabledStatus(props.goods.specs, getPathMap(props.goods.skus))
    // 触发change事件将sku数据传递出去
    const selectedArr = getSelectedArr(props.goods.specs).filter(v => v)
    if (selectedArr.length === props.goods.specs.length) {
        const pathMap = getPathMap()
        const skuIds = pathMap[selectedArr.join(spliter)]
        const sku = props.goods.skus.find(sku => sku.id === skuIds[0])
        // 传递
        emit('change', {
            skuId: sku.id,
            price: sku.price,
            oldPrice: sku.oldPrice,
            inventory: sku.inventory,
            specsText: sku.specs.reduce((p, n) => `${p} ${n.name}：${n.valueName}`, '').replace(' ', '')
        })
    } else {
        emit('change',{})
    }
}

</script>

<style scoped lang="less">
@import '@/assets/styles/variables';

.sku-state-mixin () {
    border: 1px solid #e4e4e4;
    margin-right: 10px;
    cursor: pointer;
&.selected {
    border-color: @xtxColor;
}
&.disabled {
    opacity: 0.6;
    border-style: dashed;
    cursor: not-allowed;
}
}
.goods-sku {
    padding-left: 10px;
    padding-top: 20px;
    dl {
        display: flex;
        padding-bottom: 20px;
        align-items: center;
        dt {
            width: 50px;
            color: #999;
        }
        dd {
            flex: 1;
            color: #666;
            > img {
                width: 50px;
                height: 50px;
                .sku-state-mixin ();
            }
            > span {
                display: inline-block;
                height: 30px;
                line-height: 28px;
                padding: 0 20px;
                .sku-state-mixin ();
            }
        }
    }
}
</style>
